In a conventional fuel-injection system according to CH-A5 668 621, the injection amount, with the opening cross section of the injection opening being given, is determined primarily by the fuel pressure existing in front of the opening valve. It is thereby supplied constantly or to a certain degree variably by changing the pressure corresponding with the injection pressure map fixed in a control device. It is hereby a disadvantage that through wear or obstruction of an opening cross section the injection amount changes almost linearly and thus influences the resulting motor torque. This cannot be detected by the injection system, for example, just like, tears in the area of the injection opening or also a breakage of a nozzle tip cannot be detected. This conventional injection system furthermore has inadequacies during accumulation of excessive oil-leakage amounts, for example, during a line breakage. It is possible in such cases for large amounts to escape unnoticed into the environment. Damage to the nozzle tip or other breakdowns of the injection valves possibly may not be recognized in this common injection system and can endanger users. Furthermore the problem exists in large-volume diesel motors that an abrasive, very inexpensive heavy oil is used for the control of the injection elements. Practice has shown that because of this heavy oil a satisfactory functioning of these injection elements over a longer period of time is not guaranteed.
The purpose of the present invention is to provide a fuel-injection system according to the above-described type, by means of which changes or damages within the system can be immediately recognized and corrected, to thereby achieve an optimum behavior of the internal combustion engine with respect to fuel consumption, noise and pollution emissions, and in addition, to overcome the additional above-mentioned disadvantages.